Our brains work on several different levels. On the most basic level, the brain controls the mechanisms of our body, regulating the functions of our organs. The brain ensures that the body is protected and healthy, but the brain also allows us to analyze and conceptualize complicated ideas. To put it simply, the brain is so complex that it is not completely understood by scientists.
Recent studies have shown that the brain reacts to emotional stimuli in the same way that it reacts to physical stimuli. The University of Michigan Medical School conducted an experiment in which they found that the brain processed emotional pain, such as rejection, very similarly to how it would process physical pain. When your body is feeling physical pain, the brain releases chemicals to help dull the pain. Those same chemicals are released when the body is feeling emotional stress. Those chemicals can impede brain functions such as critical thinking. The same idea applies to a person who is feeling elated. The brain releases greater levels of the neurotransmitter serotonin, which in turn makes the body feel better. Greater levels of serotonin has been linked to increased attentiveness and cognition.